This invention relates to deoiling, and more particularly, to removing oil from spent catalysts.
Spiraling oil costs, extensive price fluctuations, and artificial output limitations by the cartel of oil producing countries (OPEC) have created instability and uncertainty for net oil consuming countries, such as the United States, to attain adequate supplies of high quality, low-sulfur, petroleum crude oil (sweet crude) from Saudi Arabia, Nigeria, and other countries, at reasonable prices for conversion into gasoline, fuel oil, and petrochemical feedstocks. In an effort to stabilize the supply and availability of crude oil at reasonable prices, Amoco Oil Company has developed, constructed, and commercialized within the past year extensive, multi-million dollar refinery projects under the Second Crude Replacement Program (CRP II) to process poorer quality, high-sulfur, petroleum crude oil (sour crude) and demetallate, desulfurize, and hydrocrack resid, to produce high value products, such as gasoline, distillates, catalytic cracker feed, coke, and petroleum feedstocks. The Crude Replacement Program is of great benefit to the oil consuming nations by providing for the availability of adequate supplies of gasoline and other petroleum products at reasonable prices while protecting the downstream operations of oil refining companies.
Amoco Oil Company's Crude Replacement Program advantageously utilizes ebullated expanded bed reactors for its resid hydrotreating units (RHU). In ebullated bed reactors, oil and hydrogen flow upward through a fixed amount of catalyst. The oil flows upwardly through the catalyst bed at a sufficient velocity to expand and maintain the catalyst in a state of random ebullated motion. Ebullated bed reactors were selected over fixed bed reactors because of the ebullated bed reactor's ability to economically process more types of feedstocks as well as their ability to readily adapt to changes in the feedstocks' composition. Ebullated bed reactors desirably accommodate the addition and the withdrawal of catalyst onstream during regular use and operation without shutting down the unit and they also minimize bed plugging.
The successful commercialization and use of ebullated bed reactors requires large amounts of catalyst to be transported to and removed from the ebullated bed reactors daily. It also requires that used spent catalyst be deoiled before being shipped to a reclamation site or disposal area to protect the environment by preventing oil from dripping, spilling, and accumulating on the nation's highways as well as to maximize product yield. In order to safeguard and protect the reactors and associated refinery equipment, it is desirable to restrict trucks from driving anywhere close to the reactors and associated equipment. All of the above requirements create an enormous materials handling problem.
Over the years, many methods for processing oil, separating liquids and solids, and classifying an assortment of materials have been suggested using various augers, screw conveyers, and other classifiers. Typifying these methods are those found in U.S. Pat. Nos. 246,706, 989,915, 1,109,728, 1,685,534, 1,694,361, 2,074,988, 2,090,191, 2,189,419, 2,427,388, 2,457,461, 2,547,577, 2,662,851, 2,772,224, 2,792,098, 2,804,670, 2,886,902, 2,909,872, 2,987,185, 3,031,807, 3,170,770, 3,227,261, 3,242,057, 3,243,264, 3,322.,283, 3,498,839, 3,616,932, 3,804,670, 4,002,559, 4,125,437, 4,287,058, 4,311,561, 4,335,363, and 4,384,955. These methods have met with varying degrees of success.
It is, therefore, desirable to provide an improved deoiling process for use with resid hydrotreating units which overcomes many of the above problems.